Retrospective Analysis of Discrepancies in Malaria Diagnosis Based on Rapid Diagnostic Test Blood Smear in Japanese International Cooperation Agency Volunteers Dispatched to Sub-Sahara African Countries

When diagnosis of malaria is made by the Japan Overseas Cooperation Volunteers (JOCV) in sub-Sahara African countries, we have sometimes noted discrepancies between the results of the malaria rapid diagnostic test (RDT) and the results of the microscopic examination of blood smears (Slide test).

Therefore, we retrospectively investigated the possible reasons for the occurrence of these discrepancies, in order to re-establish the health care measures for JOCV.

We analyzed the cases of 33 patients who were diagnosed as having malaria by JOCVs or local doctors, and for whom malaria treatment was started. For 22 out of 33 patients, both RDT and a Slide test were performed. The results of the tests were identical in 10 cases (45%) and not identical in 12 cases (55%).

Twenty-two out of 33 patients were given the final diagnosis of malaria by local or Japan International Corporation Agency physicians. The concordance rate between the final diagnosis and the test result was 96% in the RDT group and 80% in the Slide test group. Among 9 patients whose test results were RDT-positive and Slide test-negative, 6 had already started Emergency Standby Medicine before the Slide test was performed at the hospitals.

The slide test is the gold standard for malaria diagnosis, and RDT is regarded as a supplementary test in developed countries. However, the accuracy of RDT results is confirmed by the WHO based on comprehensive studies and is recommended for use in developing countries where medical resources are insufficient. The promotion of the use of RDT is strongly recommended for the health care of JOCVs employed in such areas.

[ Kansenshogaku Zasshi 92: 533-537, 2018 ]

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